1. Field of the Invention
The invention relates generally to the field of water bottom deployed, remotely operated drilling and coring apparatus. More specifically, the invention relates to devices for taking large volume samples of sediments from below the bottom of a body of water.
2. Description of the Related Art
U.S. Patent Application Publication No. 2006/0016621 filed by Jackson et al. discloses a system for taking core samples below the bottom of a body of water. The system disclosed in the '621 publication includes a drilling platform positioned on the bottom of a body of water; a surface vessel; and a submersible robotic vehicle movable between the underwater drilling platform and surface vessel. The robotic vehicle performs one or more of the following underwater operations: (i) providing power to the underwater drilling platform; (ii) monitoring and/or controlling the operation of the underwater drilling platform; (iii) assembling drill rods to form a drill string; and (iv) recovering a core barrel from the drill string and transporting the core barrel to the surface. In one embodiment, the underwater drilling system includes a shuttle movable between the surface vessel and underwater drilling platform. The shuttle carries one or more of a tool, rod, and core barrel between the surface vessel and the drilling platform.
U.S. Pat. No. 3,670,830 issued to van der Widjen describes a drilling apparatus that is positioned on the ocean floor for cutting a borehole in the floor and removing samples therefrom. The drilling apparatus has a drilling head which is detachably coupled to a string of pipes all detachably connected together by connecting devices which are engageable by axial pushing of the pipes together. The pipes carry inner tubes which cooperatively form an inner annular cavity and a core member is detachably connected to the lowermost inner tube of the drill string by spring-loaded latches. When a core sample is in the core tube it is detached by fluid pressure in the space between the outer pipes and the inner tubes and the core barrel is then pumped upwardly and stored in a turntable containing further drill pipes and core barrels. A further drill pipe is connected in the string and a further core barrel is dropped into the inner tubes of the string and connected to the lowermost inner tube pressurizing fluid in the inner tubes.
The foregoing drilling and sample taking devices are generally configured to drill core samples from the sediments below the water bottom. Some types of water bottom sediments contain economically valuable minerals, such as heavy metals. The valuable minerals may be dispersed in the sediments below the water bottom, and determining the presence and concentration of such valuable minerals may require that large volumes of sediment are sampled if using the core drilling devices known in the art. There exists a need for a device that can sample large volumes of water bottom sediment, with the capacity to segregate the samples to reduce the volume of samples retrieved to the water surface for analysis.